Question

Which is not a key step in the process of translation?

• A. The sequence of nucleotides on the tRNA is read in triplets called codons.
• B. Termination of translation occurs when a stop codon is reached.
• C. Amino acids link together with peptide bonds to form a growing chain.
• D. tRNA enter the A, P and E sites on the ribosomes to drop off a specific amino acid and then leave.

Answer 1

The correct option is A The sequence of nucleotides on the tRNA is read in triplets called codons.

Protein synthesis in living cells is also called as translation. It is the process of synthesizing a protein from an mRNA template. The mRNA is loaded onto the ribosome and is read three nucleotides at a time by matching each codon to its base pairing anticodon located on a transfer RNA (tRNA) molecule, which carries the amino acid corresponding to the codon it recognises. The enzyme aminoacyl tRNA synthetase charges the tRNA molecules with the correct amino acids and occupies the a, P, E site on the small subunit of the ribosome in a stepwise manner to form a peptide. The growing polypeptide is often termed the nascent chain. Proteins are always biosynthesized from N-terminus to C-terminus. Therefore, the ( triplet) codon is present on mRNA and not on tRNA. Thus, the correct answer is option A.